Sterilization of medical equipment and accessories is of paramount importance in the proper operation of a hospital, clinic, private doctor's office or dentist's office. To effectively sterilize instruments and equipment, highly resistant spores must be killed as well as vegetative bacteria, fungi and virus.
Prior to the present invention, effective sterilization of, for example, surgical instruments has been accomplished in hospitals primarily by either autoclaving or by exposure of the instruments to ethylene oxide. Autoclaving is steam sterilization in which the instruments and other materials to be sterilized are exposed to high temperature and high pressure. Autoclave chambers are expensive to own and to operate. The chambers must be periodically tested with spore strips to assure continuing effectiveness, temperature and pressure must be constantly monitored by the user, and periodic maintenance must be performed. Sterilization by ethylene oxide requires expensive ethylene oxide chambers in which the materials can be exposed to the ethylene oxide in a vacuum for good penetration. Once the materials have been treated with the ethylene oxide, a number of hours must lapse before the materials can be used to allow for evaporation of toxic gases from the materials. In industrial applications, oftentimes ionizing radiation is used as a sterilization method. Each of the typical prior sterilization methods is very expensive, thus tending to restrict their availability to hospitals and other large institutions. Such methods are generally beyond the financial grasp of small firms of private physicians and dentists. Furthermore, typical prior art sterilization methods require a long period of time, generally in excess of eight hours, to complete proper sterilization of the materials. Therefore, a user of the prior sterilization methods must bear the added expense of owning a number of separate sets of instruments and other materials in order that there is one set on hand while the others are being sterilized.
When sterilization by the foregoing methods is impracticable, for financial or other reasons, physicians and dentists can disinfect instruments by use of cold baths of chemical solutions. The majority of the most commonly used known disinfectants, although they are often effective for killing vegetative bacteria and fungi, are incapable of killing spores such as tetanus and hepatitis spores. Many of the most effective disinfectants such as glutaraldehyde, formaldehyde, phenol and chlorine possess undesirable qualities. For example, the disinfectant may be toxic, it may develop noxious fumes, cause skin irritation or allergic reaction. More importantly, glutaraldehydes and phenols have recently been placed on the list of carcinogens as being probable cancer forming agents. Whenever possible, these disinfectants are being removed from the market.
Quaternary ammonium compounds can be used as effective disinfectants against gram positive organisms, especially streptococcus and staphylococcus. Quaternary ammonium compounds are non-toxic, essentially odor free, non-allergenic and otherwise are physiologically safe, but are among the least effective disinfectants when used alone. For example, quaternary ammonium compounds are relatively ineffective against gram negative organisms, and do not effectively kill spores.